The present invention relates generally to test and diagnosis systems for machines or other operating apparatus, and has particular application to automotive vehicles, particularly vehicles powered by internal combustion engines. While the invention is described in the context of an engine analyzer system, the principles of the present invention are usable with other types of vehicle diagnostic systems, such as air conditioning testing and servicing systems, wheel balancing systems, automotive gas emissions analysis systems, and the like, and are also usable with non-automotive apparatus.
A number of different types of diagnostic tools have been heretofore used to assist in diagnosis and repair of fault conditions in automotive vehicles. Such tools include engine analyzers, which are designed to monitor a variety of operating conditions of an internal combustion engine, and scanners for downloading data from vehicle on-board computers. In addition, diagnostic tools may include such standard laboratory-type tools as laboratory oscilloscopes, digital volt-Ohm meters (xe2x80x9cDVOMxe2x80x9d) and the like. Basically, these various diagnostic tools fall into two categories, data providers and platform diagnostics, although some engine analyzers, such as that disclosed in U.S. Pat. No. 5,250,935, can interface with scanners and can operate in a mode simulating a lab scope and/or a DVOM.
Data providers (e.g., DVOMs, scanners and laboratory oscilloscopes), simply give the user data, and the user must determine his own diagnostic test procedures and conclusions. Data provider tools rely completely on the user""s ability to decide which tool to use and what to do with the data provided, including selection of tests which should be performed, interpreting the test results and the like.
Platform products, e.g., engine analyzers, are typically high-end systems capable of performing a variety of different types of tests. They may provide the user with automatic test sequences that systematically test the vehicle in a particular order and then provide diagnostic conclusions based on the test results. Platform products, such as engine analyzers, are usually focused on particular types of problems or particular vehicle systems. They may take considerable time to hook up all the necessary leads and perform the comprehensive tests, and the user must decide which product to use and how the test data should be integrated into an overall diagnosis.
There are also information systems available as stand-alone software packages which provide service and repair information for a wide variety of automotive vehicles. However, such products are difficult to navigate through to find the information needed for diagnosis and repair and they are typically based only on original equipment diagnostic information, and may not contain information on problems experienced in the field over the life of the vehicle.
It is a general object of the invention to provide an improved diagnostic system which avoids the disadvantages of prior such systems while affording additional structural and operating advantages.
An important feature of the invention is the provision of a diagnostic system which will guide the user in the selection of tests to be performed and minimize the performance of needless tests.
In connection with the foregoing feature, a further feature of the invention is the provision of a diagnostic system of the type set forth which permits fault-based selection of tests.
Yet another feature of the invention is the provision of a diagnostic system of the type set forth which facilitates modification and updating to include information on problems and cures experienced in the field over the life of an apparatus under test.
Still another feature of the invention is the provision of a diagnostic system of the type set forth which can be readily integrated with pre-existing diagnostic hardware platforms.
In connection with the foregoing feature, a still further feature of the invention is the provision of a diagnostic system of the type set forth which is modular.
Yet another feature of the invention is the provision of a diagnostic system of the type set forth, which is designed to rank selected tests in an order most likely to successfully diagnose an apparatus problem.
Another feature of the invention is the provision of a diagnostic system of the type set forth which includes storage of the results of user applications of the system, for later incorporation in system updates.
The invention consists of certain novel features and a combination of parts hereinafter fully described, illustrated in the accompanying drawings, and particularly pointed out in the appended claims, it being understood that various changes in the details may be made without departing from the spirit, or sacrificing any of the advantages of the present invention.